I can tell you one thing, that's not how they work. It happens from time to time (Jason Bay to the Red Sox), but if you look at the Yankees and especially the Red Sox (the two biggest fish in the AL market wise), they have made it a priority recently to have good minor league systems not only for the purpose of trading them off to small market teams, but also in order to work them into the lineup.

Successful teams even more than major market teams have made it a priority to develop good teams in the major leagues while maintaining a good personnel in the minor leagues.

Recent is a relative term, who did Josh Beckett pitch for before joining the Red Sox?

And what has Kenny williams done with the talent from the White Sox farm system in recent years? And what percentage of the fan base knew who Chris Young was when he was traded, or Jeremy Reed? (Not to be confused with Jimmy Reed because he stubbornly remains dead.)